An object having three-dimensional surface such as an automotive vehicle body is painted by painting mechanisms movable along a transfer path near the object. Each of the painting mechansims has a plurality of paint spray guns displaceable dependent on the surfaces to be painted, the paint spray guns being adjustably located at optimum distances and angles with respect to the surfaces to be painted for applying a uniform paint coat to the object. No pain runs and sags will be formed on the coated surfaces.
